International Journal of Applied Chemistry

The corrosion inhibition characteristics of benzaldehyde thiosemicarbazone and it's p-substituted derivatives on corrosion of Fe₇₈B₁₃Si₉ metallic glass alloy in 0.2M Na₂SO₄ were investigated at different temperature (20, 30, 40, 50, 60°C). Presence of chloride ion in inhibitor free test solution has accelerated effect on alloy corrosion while opposite behavior is observed by bromide ion. Electrochemical results indicated that all the investigated compounds were acted as mixed type inhibitors at elevated temperatures. The trend of inhibition efficiency with temperature to be suggested physical adsorption of these compounds on the corroding amorphous surface. The observed inhibition action for NaCl or NaBr with benzaldehyde thiosemicarbazone compounds was explained to be due to a joint adsorption of both the inhibitors and halide ion on amorphous surface and tow suggested schemes were drown. Thermodynamic functions ΔE_app, ΔH* and ΔS* has been calculated and are discussed in absence and presence of halide ions.